Order Processing Pipeline Diagrams

🔄 Sequence Diagram

The sequence diagram below shows the temporal flow of messages between components.

sequenceDiagram
    autonumber

    participant FE as Frontend Web App
    participant GW as API Gateway
    participant OS as Order Service
    participant DB as Database
    participant Q as Message Queue
    participant PS as Payment Service
    participant PP as External Payment Provider
    participant NS as Notification Service
    participant IS as Inventory Service
    participant AS as Analytics Service

    FE->>GW: Submit Order (POST /orders)
    GW->>OS: Forward Request
    OS->>DB: Insert Order Record
    DB-->>OS: Success


    OS->>Q: Enqueue "OrderCreated" Message
    Q-->>OS: Ack

    Note over Q,PS: Payment Service consumes messages asynchronously

    PS->>Q: Dequeue OrderCreated
    Q-->>PS: Message + Visibility Timeout

    PS->>PP: Charge Customer
    PP-->>PS: Payment Result (Success/Failure)

    alt Payment Success
        PS->>OS: Update Order Status (Paid)
        OS->>DB: Update Order Row
        DB-->>OS: Success

        OS->>NS: Emit "OrderPaid" Event
        OS->>IS: Emit "InventoryUpdate" Event
        OS->>AS: Emit "OrderAnalytics" Event
    else Payment Failure
        PS->>OS: Update Order Status (Failed)
        OS->>DB: Update Order Row
        DB-->>OS: Success

        OS->>NS: Emit "PaymentFailed" Notification
        OS->>AS: Emit "OrderAnalytics" Event
    end

    NS-->>FE: Send Email/SMS Notification
    IS->>DB: Decrement Inventory
    AS->>DB: Write Analytics Data